“The word God is for me nothing more than the expression and product of human weaknesses, the Bible a collection of honorable but still primitive legends which are nevertheless pretty childish.”
-Albert Einstein (letter written by Albert Einstein to the philosopher Eric Gutkind in January 1954)

From a correspondence between Ensign Guy H. Raner and Albert Einstein in 1945 and 1949. Einstein responds to the accusation that he was converted by a Jesuit priest: "I have never talked to a Jesuit priest in my life. I am astonished by the audacity to tell such lies about me. From the viewpoint of a Jesuit priest I am, of course, and have always been an atheist." "I have repeatedly said that in my opinion the idea of a personal God is a childlike one.You may call me an agnostic, but I do not share the crusading spirit of the professional atheist whose fervor is mostly due to a painful act of liberation from religious indoctrination received in youth." Freethought Today, November 2004

He sais quite specifically that the only concept of god that he had is the embodiment of the laws of the universe. He was an atheist. No doubt. From what I understand his few struggles with religion were due to the devotion of his wife.

I have over the years read all the Einstein quotations. He meets my personal definition of atheist.

"I have repeatedly said that in my opinion the idea of a personal God is a childlike one.”

I get the sense from the whole body of quotes that he used the word “god” in much the same way that I might use the designation “mother nature”; that is as a sort of personification of the universe and the laws of nature.